1. Field of the Invention
The present invention relates generally to the field of prefabricated concrete wall construction, and more specifically, to a prefabricated concrete stud wall panel and method of forming the same.
2. Description of the Prior Art
In response to problems with traditional block construction methods, prefabricated wall panels were developed for rapid construction of buildings. Prefabricated wall panels are shown in U.S. Pat. Nos. 4,751,803, 4,934,121, 5,055,252 and 5,313,753. Two types of prefabricated concrete walls which are commonly used are cavity walls having open pockets between spaced vertical studs and planar walls having insulation panels between the vertical studs to form a substantially planar surface. While both of these types of prefabricated wall panels are generally superior to traditional block construction in terms of costs, performance and reliability, there are still problems associated with both.
Many cavity walls use preformed concrete studs from a prior pour where they are formed separately from the top and base beams. A subsequent pour is then necessary to integrate the vertical studs with the top and base beams. As a result, walls formed in this manner require additional pouring and curing time and are often weaker than walls formed from a monolithic pour. Monolithic concrete cavity walls are typically formed by pouring concrete into frames which have forming channels for the vertical studs and the top and base beams. However, it is often difficult to remove the finished wall panel from the forming channels without damaging the concrete studs or beams.
In addition to the above, it is often necessary to provide a wood stud at the face of the concrete studs. This is often accomplished by laying wood strips in the forming channels prior to pouring. Typically, the wood strips have a series of nails projecting therefrom and the concrete cures around the nails to secure the wood studs. The process of providing nails in each of the wood strips is time consuming and adds to the manufacturing costs. Additionally, the wood strips are susceptible to cracking and warping, particularly when they are exposed to the wet concrete.
The planar walls are typically formed by placing wall studs, insulation, and reinforcing means in a forming assembly and filling the assembly with concrete. The studs and insulation are generally provided with projections which are surrounded by the concrete to integrate the studs and insulation into the wall. Planar walls which utilize wood studs often experience the same problems as the cavity walls do. U.S. Pat. Nos. 5,313,753 and 5,381,635 suggest mounting other common studs, metal or plastic studs, to the front faces of the concrete studs. However, these studs are merely secured to the front of the concrete studs by narrow flanges which may pull from the concrete. As the size of the flanges is increased, the chance that the concrete will fail to flow between and around the flanges also increases. Another problem associated with these metal and plastic studs on the vertical concrete face is that there is no way of passing service lines, such as, plumbing and electrical wiring, through the vertical studs.
Accordingly, there exists a need for a monolithic concrete wall which is easy to form, includes integral attachment stud surfaces and overcomes the disadvantages of the prior art.
The present invention generally relates to a stud form of a type used in forming a preformed concrete wall panel having a solid portion and a plurality of vertical concrete studs joined to the solid portion. The stud form includes a substantially U-shaped channel having a face portion that defines an elongated plane and leg portions extending along side of and away from the elongated plane to define a predetermined channel depth. The stud form further includes means for integrally connecting the stud form to the solid portion of the wall panel with the channel opened toward the solid portion.
The present invention also includes preformed concrete walls which incorporate the stud form and a system for forming such.